1. Field of the Invention
This invention concerns a non-contact reader which includes a reading device arranged to read information from an information medium without mechanical or galvanic contact, and generate a meaningful signal at the output of the reading, device when the information medium is brought into proximity with the reading device, and a test device to test the correct operation of the reading device.
2. Description of Related Art
Non-contact readers with corresponding identification means are known and are marketed in various embodiments.
Such known readers comprise test devices which test the electronic circuit of the reader for correct operation by measuring and evaluating electrical parameters obtained by electrical contact with parts of the circuit.
However, in this way it is never possible to demonstrate the correct operation of the wireless part of the reader with certainty. This is nevertheless essential for judging whether the reader works correctly or not, since the absence of the meaningful signal at the output of the reader is interpreted as the absence of an identification means within range of the reader. DE-A-R.132.973 describes a barcode reader in which the test device includes means to vary the illumination strength of the sensor, for example by altering the light output of the light source, and to evaluate the output signals generated as a result. These means are operated manually by pressing a test button. The testing is carried out while reading a normal identification means introduced into the reader. With this known reader, testing is fairly complicated, while the test device is not simple in construction and demands special modification of the reader, making it expensive.
U.S. Pat. No. 4,868,375 describes a barcode reader whose function can be modified by inserting an identification means with a special barcode. The modified function, for example a diagnosis function, is only started after such a special barcode has been read in. With this reader, testing is fairly complicated and laborious since a medium with a special barcode has to be made and inserted into the reader each time testing is carried out.